Power over Ethernet system having multiple power source devices and control device thereof

ABSTRACT

Control device for power over Ethernet system having multiple power source devices controls power distribution to a plurality of communication ports. Master controller provides a power supply to power consumption look-up-table to a plurality of control circuits in various manners via a series bus. When one power source device shuts down, each control circuit can rapidly shut off selected port switches connected thereto.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a power-over-Ethernet (PoE) system anda control device useful in the system, in particular to a PoE systemwith a plurality of power source devices, and a control device used insuch a system.

BACKGROUND OF THE INVENTION Prior Art

In a wired communication network, supplying electrical power to deviceson the network through network cables is already a mature technology.For example, the Power over Ethernet (PoE) power supply system, which ispowered by the wiring of the Ethernet, has gradually become popular, dueto its advantages in reducing installation costs, as well as centralizedpower supply and power backup, and safety management. Currently most PoEsystems follow the IEEE 802.3af-2003 standard, which is incorporatedherein for reference.

The PoE system provides a scalable function, with which in the initialoperation stage, the system can automatically or manually configure itspower distribution to the limited number of communication ports in thesystem. As time passes, the system can also detect the power supplystate automatically, and increase or decrease the number of ports toreceive electrical power, based on the detection results in the powersupply state. Each communication port is connectable by one powerconsuming device, to receive electrical power from the system.

There are methods to increase power supply in a PoE system. One of themethods is to use multiple power source devices or multiple groups ofpower supply. The plurality of power source devices is connected to oneor more control element in parallel, which control element then suppliesor distributes the electrical power of the plural power source devicesto individual power consuming devices. Power source devices of non-PoEsystem can also apply power to the PoE system, to increase its suppliedpower, as long as the sum of the PoE power supply and the non-PoE powersupply can be distributed to one or more loads via Ethernet wire/cables.

In a power supply system wherein a plurality of power source device isused, an important technical problem to be overcome is how toimmediately stop supplying power to particular power consuming devices,i.e., to particular ports, when one or more of the plural power sourcedevices shuts down or reduces its output power, in order to avoid theoccurrence of overloading on the remaining supplied power. Further, inorder to prevent impacts on the remaining power consuming devices due toa shutdown or low-power status, it is also necessary to stop supplyingpower to the particular power consuming devices immediately or within avery short time, usually within 20 ms, preferably within 2 ms. If thetotal power consumption of all the connected power consuming devicescannot be reduced within that period, the total system would shut downduring the emergency power-off operation.

The prior art has proposed several solutions to this demand, especiallymeans to quickly stop supplying power to sufficient number of powerconsuming devices, when one or more power source devices fail.

U.S. Pat. No. 7,337,336 No. discloses a “Method for rapid port powerreduction,” useful in a PoE system with multiple power source devicesand allowing quickly reducing or stopping power supplied to particularports, when the power supply state changes. The method comprises thesteps of: Coding of possible power supply states. For example, if thesystem has 4 power source devices, code 1 is assigned to a power sourcedevice in normal operation, while code 0 is assigned otherwise. In thisway, 16 power supply state codes can be assigned to represent allpossible power supply states. For each of the 16 power supply statecodes, a power supply index is assigned, which index indicates ports tobe supply power (code 1) and ports not to be supply power (code 0). Allpower supply state code-power consuming index assignments thus form alook-up-table. When the power supply state of any power source devicechanges, the change is detected, whereby a new power supply state codeis generated. Thereupon, a new power consuming index combination ispicked up from the look-up-table, and executed. That is, power suppliedto ports coded 0 is shut off, while power supplied to ports coded 1 ismaintained.

U.S. Pat. No. 7,908,494 discloses a system and method for multiple powerover Ethernet (PoE) power supply management. Power supply state signalsindicative of an operating condition of a plurality of PoE powersupplies are provided to a plurality of power sourcing equipment (PSE)controller chips. Pre-configured combination logic within each of thePSE controller chips converts an indicated operational state of theplurality of PoE power supplies into a powering decision for each of theEthernet ports served by the PSE controller chip within one microsecond.

Although the immediate power shutting off operation is activated by achange in the power supply state combination, an operation would beactivated wherever the power supply state of one power source devicechanges. It is possible to wire together the power supply state signalswith a single state input signal and use the single state input signalto activate the change. This is disclosed in U.S. 2007/0250218, title ofthe invention: Power management logic that reconfigures a load when apower supply fails.

A method for immediately shutting off power supply to predeterminedports upon change of power supply state is disclosed in TW 2017/29564,“Power source devices and method for power over Ethernet power supplysystem.” The method continuously detects specific communication ports toobtain the power consumption value along the time axis of the powerconsuming devices connected to the communication ports, and thendetermines a power consumption trend value. When the trend value showsthat the power consumption of a power consuming device exceeds a powersupply upper limit for a predetermined time, the power supply to thepower consuming device is stopped.

It can be known from the prior art that, although the conventionalemergency power-off mechanism can quickly shut off certain ports, it isonly suitable for systems with a small number of power consumingdevices. When the number of power consuming devices reaches aconsiderable level, especially when the ratio of the number of powerconsuming devices to the number of power source devices is great, thelength of the assigned code will be too long and the selectivity will begreatly reduced. Shutting off power supply to particular ports willbecome difficult.

In addition, when the ratio of the number of power consuming devices tothe number of power source devices is too high, the selectivity ofcommunication ports for shutting off will be limited; it is not possibleto select the target ports dynamically. Therefore, the scalabilityrequirements of the PoE system cannot be met.

SUMMARY OF THE INVENTION

One objective of the present invention is to provide a control devicefor power over Ethernet system having multiple power source devices,which can rapidly reduce or stop the electrical power supplied tospecific ports when a power source device fails.

Another objective of the present invention is to provide a controldevice for power over Ethernet system having multiple power sourcedevices, which can rapidly reduce or stop the electrical power suppliedto specific ports when a power source device fails, and is suitable fora system with a greater number of power source devices and powerconsuming devices.

Another objective of this invention is also to provide a control devicefor power over Ethernet system having multiple power source devices,which can rapidly reduce or stop the electrical power supplied tospecific ports when a power source device fails, and can dynamicallyselect appropriate power consuming device to reduce or stop the powersupply in compliance with the reduction or increase in the number of thepower consuming devices.

Another objective of the present invention is also to provide a controlmethod useful in the above-mentioned control device for PoE system withmultiple power source devices.

According to a first aspect, the present invention provides a controldevice for power over Ethernet system having multiple power sourcedevice. The control device comprises:

a master controller, comprising:

an input terminal, for connecting a plurality of power source devices toreceive a power supply state signal representing a combination of powersupply state of the plurality of power source devices;

a detection circuit connected to the input terminal for detecting thepower supply state signal and for generating a power supply state changesignal, when a power supply state signal received by the detectiondevice is different from a previously received power supply statesignal;

a first look-up-table memory to store a power supply to powerconsumption look-up-table defining a corresponding relation of aplurality of power supply state combination to a plurality of powerconsumption control combination; and

a control signal generating circuit connected to the detection circuitand configured to: generate, upon receipt of a power supply state changesignal, a power supply state code corresponding to the received powersupply state signal;

a plurality of control circuit connected to the master controller and aplurality of port switch, each port switch controlling a powerconsumption state of at least one port to be connected by a powerconsuming device; each control circuit being configured to generate,upon receipt of the power supply state code, a power consumption controlsignal corresponding to the power supply state code and to provide thepower consumption control signal to corresponding port switches, todetermine a power ON/OFF state of corresponding ports; and

a signal bus connected to the master controller and the plurality ofcontrol circuits; wherein, the signal bus is a serial bus. In apreferred embodiment of the present invention, the signal bus uses theIIC communication protocol.

In the preferred embodiments of the present invention, each controlcircuit may further comprise a second look-up-table memory, to store asecond power supply to power consumption look-up-table, defining acorresponding relation of a plurality of power supply state combinationand a plurality of power consuming control combination, wherein each ofthe plurality of power consuming control combination corresponds to apower consuming state combination of port switches in connection withthe control circuit.

In the preferred embodiments of this invention, the first and/or secondpower supply to power consumption look-up-table defines a correspondingrelation between a plurality of power supply state signals and aplurality of power consumption control signals, and/or between aplurality of power supply state codes and a plurality of powerconsumption control signals.

In such embodiments, the master controller may be configured to: in theinitial stage of the system, provide the first power supply to powerconsumption look-up-table stored in the first look-up-table memory tothe plurality of control circuit; the control signal generating circuitis configured to convert, upon detection of a change in the power supplystate signal, the received power supply state signal into a code andprovide the code to the plurality of control circuits as the powersupply state code; and the plurality of control circuit is configuredto: after receiving the first power supply to power consumptionlook-up-table provided by the master controller, store the first powersupply to power consumption look-up-table in the second look-up-tablememory, and to pick up, after receiving the power supply state code, onecorresponding power consumption control signal from the power supply topower consumption look-up-table stored in the second look-up-table, andprovide the power consumption control signal to port switches inconnection with the control circuit.

In a preferred embodiment of the present invention, the power supplystate signal comprises a code with the same number of digits as thenumber of the plurality of power source devices. In a specificembodiment of the present invention, the power supply state changesignal is result of a conversion of the power supply state signal.

In a specific preferred embodiment of the present invention, the powersupply state change signal is the result of converting the receivedpower supply state signal into a serial signal. In this embodiment, theat least one control circuit picks up a power consumption control signalcorresponding to the power supply state change signal from the powersupply to power consumption look-up-table.

In such preferred embodiments of the present invention, the at least onecontrol circuit provides the picked-up power consumption control signalsto other control circuits via the signal bus; and the receiving controlcircuits are respectively configured to: provide, after receipt of thepower consumption control signals, the power consumption control signalsto the port switches connected to the corresponding control circuit.

According to a second aspect of the present invention, the presentinvention provides a control device for power over Ethernet systemhaving multiple power source devices. The system comprises:

a plurality of power source devices;

a plurality of communication ports, each communication port to beconnected by a power consuming device, to establish a signal and powerconnection with the power consuming device; each communication porthaving a port switch to control power consumption state of the port;

a control device in connection with the plurality of power sourcedevices and the plurality of communication ports via a network cable, toconvert power supplied by the power source devices into electrical poweruseful for power consuming devices connected to correspondingcommunication ports, and to generate power consumption control signalsfor control of an ON/OFF state of port switches connected thereto.

The control device comprises:

a master controller, comprising:

an input terminal, for connecting a plurality of power source devices toreceive a power supply state signal representing a combination of powersupply state of the plurality of power source devices;

a detection circuit connected to the input terminal for for detectingthe power supply state signal and for generating a power supply statechange signal, when a power supply state signal received by thedetection device is different from a previously received power supplystate signal;

a first look-up-table memory to store a first power supply to powerconsumption look-up-table defining a corresponding relation of aplurality of power supply state combination and a plurality of powerconsumption control combination; and

a control signal generating circuit connected to the detection circuitand configured to: upon receipt of a power supply state change signal,generate a power supply state code corresponding to the received powersupply state signal;

a plurality of control circuit connected to the master controller and aplurality of port switch, each port switch controlling a powerconsumption state of at least one port to be connected by a powerconsuming device;

wherein each control circuit is configured to: upon receipt of the powersupply state code, generate a power consumption control signalcorresponding to the power supply state code and provide the powerconsumption control signal to corresponding port switches, to determinea power ON/OFF state of corresponding ports; and

a signal bus connected to the master controller and the plurality ofcontrol circuits; wherein, the signal bus is a serial bus. In apreferred embodiment of the present invention, the signal bus uses theIIC communication protocol.

According to a third aspect of the present invention, the presentinvention provides a control device for power over Ethernet systemhaving multiple power source devices. The control device comprises:

a master controller, comprising:

an input terminal, to receive a power supply state signal representing acombination of power supply state of the plurality of power sourcedevices;

a detection circuit connected to the input terminal for detecting thepower supply state signal and for generating a power supply state changesignal, when a power supply state signal received by the detectiondevice is different from a previously received power supply statesignal;

a first look-up-table memory to store a first power supply to powerconsumption look-up-table defining a corresponding relation of aplurality of power supply state combination and a plurality of powerconsumption control combination; and

a control signal generating circuit, connected to the detection circuitand configured to: upon receipt of a power supply state change signal,pick up a power consumption control signal corresponding to the receivedpower supply state signal from the power supply to power consumptionlook-up-table;

a plurality of control circuit connected to the master controller and aplurality of port switch, each port switch controlling a powerconsumption state of at least one port to be connected by a powerconsuming device;

wherein each control circuit is configured to provide the powerconsumption control signal to corresponding port switches, upon receiptof the power consumption control signal, to determine a power ON/OFFstate of corresponding ports; and

a signal bus connected to the master controller and the plurality ofcontrol circuits; wherein, the signal bus is a serial bus. In apreferred embodiment of the present invention, the signal bus uses theIIC communication protocol.

In such embodiments, the control signal generating device is configuredto: upon receipt of a power supply state change signal, pick up a powerconsumption control data corresponding to the received power supplystate signal from the first power supply to power consumptionlook-up-table, to generate one or more power consumption control signal,and provide the one or more power consumption control signal to theplurality of control circuit via the signal bus. In addition, eachcontrol circuit may be configured to: upon receipt of the one or morepower consumption control signal, provide a corresponding powerconsumption control signal to a corresponding plurality of port switch.In most embodiments of the present invention, the one or more powerconsumption control signal comprises a code indicative of relatedcontrol circuits. In such embodiments, the quantity of the controlcircuit is identical or is a multiple of the number of the powerconsumption control signal.

In the preferred embodiments of this invention, the first power supplyto power consumption look-up-table defines a corresponding relationbetween a plurality of power supply state signals and a plurality ofpower consumption control signals, and/or between a plurality of powersupply state codes and a plurality of power consumption control signals.

According to the fourth aspect of the present invention, the presentinvention provides a power over Ethernet system having multiple powersource devices. The PoE system comprises a plurality of power sourcedevices, a plurality of power consuming communication ports and acontrol device with the above-described features.

According to the fifth aspect of the present invention, the presentinvention provides a control device for power over Ethernet systemhaving multiple power source device. The control device has the featuresof the first aspect of the present invention, while the mastercontroller is configured to: in the initial stage of the system, dividethe first power supply to power consumption look-up-table stored in thefirst look-up-table memory into a plurality of sub-tables and providethe sub-tables to corresponding ones of the plurality of controlcircuits; and the plurality of control circuits is configured to: afterreceiving the sub-table provided by the master controller, store thesub-table in the second look-up-table memory, and to pick up, afterreceiving the power supply state code, a corresponding power consumptioncontrol signal from the second power supply to power consumptionlook-up-sub-table, and provide the power consumption control signal tothe port switches in connection with the control circuit.

In the fifth aspect of the invented control device for power overEthernet system having multiple power source device, the mastercontroller can also be configured as one of the plurality of controlcircuits. That is, the master controller is also connected to aplurality of port switches and is configured to pick up a powerconsumption control signal corresponding to a power supply state codefrom the first power supply to the power consumption look-up-table, or asub-table thereof, after the power supply state code is generated, andto provide the picked up power consumption control signal to the portswitches in connection with the master controller.

According to the sixth aspect of the present invention, the presentinvention provides a power over Ethernet system having multiple powersources. The system comprises a plurality of power source devices, aplurality of power consuming communication ports and a control devicecomprising the above-described features.

Other objectives, features, and advantages of the present invention canbe appreciated clearly from the detailed description of the preferredembodiments by referring to the drawings. It should be noted that thedescription of the embodiments of the present invention is only intendedto illustrate the main technical content, features, and effects of thepresent invention, and is not intended to limit the scope of the presentinvention. It is obvious for the skilled persons n this industry toderive various changes and applications based on the description of theembodiments. As long as they do not depart from the scope of theattached patent claims, they are all within the scope of the presentinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic diagram of a Power over Ethernet system havingmultiple power source devices.

FIG. 2 shows a schematic structural diagram of an embodiment of theinvented control device for power over Ethernet system having multiplepower source device.

FIG. 3 shows a schematic structural diagram of a second embodiment ofthe invented control device for power over Ethernet system havingmultiple power source device.

FIG. 4 shows a schematic structural diagram of a third embodiment of theinvented control device for power over Ethernet system having multiplepower source device.

FIG. 5 shows a schematic structural diagram of a fourth embodiment ofthe invented control device for power over Ethernet system havingmultiple power source device.

DETAILED DESCRIPTION OF THE INVENTION

In the following, several embodiments of the invented power overEthernet system having multiple power source devices and its controldevice will be described by reference to the drawings, so to demonstratethe design, features and effects of the present invention.

FIG. 1 shows a schematic diagram of a Power over Ethernet system havingmultiple power source devices. The PoE system having multiple powersource devices in which the invented control device is used, is alreadya known technology. A PoE system usually comprises a plurality of powersource devices 201-204, a plurality of communication ports 301, 302,303, . . . 30N, and a control device 400. As is well known, theplurality of power source devices 201-204 are usually a computerequipment or a network equipment, but may also be simply a power supplyor other devices whose main purpose is to supply electrical power. Thecommunication ports 301, 302, 303, . . . 30N can be connected by powerconsuming devices (not shown), so to establish a signal and powerconnection with the power consuming devices. Typical power consumingdevices are networked computer equipment, network equipment, peripheralssuch as laser printers, telephones, scanners, cameras, projectors,monitors, microphones, headphones, intelligent household appliances. Itmay also be just an electrical load, such as LED lights and generalhousehold appliances. As shown in FIG. 1, each communication port 301,302, 303, . . . 30N has a port switch 311, 312, 313, . . . 31N tocontrol power supplied thereto. As will be explained below, each portswitch 311, 312, 313, . . . 31N is connected to the control device 400,and is controlled by the control device 400 to switch on or off.

The control device 400 is in connection with the plurality of powersource device 201-204 via an input terminal 411 and network lines221-22, and with the plurality of communication port 301, 302, 303, . .. 30N via signal lines 321-32N. The control device 400 convertselectrical power supplied by the power source devices 201-204 intoelectrical power useful by power consuming devices in connection withthe communication ports 301, 302, 303, . . . 30N. The power overEthernet system having multiple power source devices with the abovearchitecture, features and functions is already a mature technology andis widely used all over the world. There are also detailed descriptionsin the prior art disclosures mentioned above. Readers can refer to them,if necessary for further research.

The main objective of the present invention is to provide a controldevice 400 with a novel architecture and a control method applicable inthe control device 400, to distribute the electrical power of theplurality of power source devices 201-204 to the plurality ofcommunication ports 301, 302, 303, . . . 30N, especially when one of theplurality of power source devices 201-204 fails, so that the electricalpower provided by the remaining power source devices may be properlydistributed to the plurality of communication ports 301, 302, 303, . . .30N.

FIG. 2 is schematic structural diagram of one embodiment of the inventedcontrol device for PoE system having multiple power source device. Asshown in this figure, the control device 400 includes a mastercontroller 410, a plurality of control circuits 421-42N, and a signalbus 430 connecting the two. The other end of the plurality of controlcircuit 421-42N is respectively connected to the port switches 311-31N,and each port switch 311-31N controls the power consuming state of atleast one communication port 301-30N, and each communication port301-30N can be connected by a power consuming device, so that electricalpower and/or signal is provided to each power consuming device.

Also shown in the figure, the master controller 410 has an inputterminal 411, which includes a plurality of power connectors forconnecting a plurality of power source devices 201-204, to receive apower supply state signal representing a combination of power supplystates of the plurality of power source devices. FIG. 2 shows that theinput terminal 411 is connected to 4 power source devices 201-204.However, the number of power source devices that a PoE system can use isnot particularly limited. In addition, although the main purpose of thepower connectors is to detect and control, it can also be thetransmission channel of the electrical power for the power sourcedevices 201-204, for supplying power to the plurality of communicationports 301, 302, 303, . . . 30N.

The detection circuit 413 is connected to the input terminal 411, fordetecting the power supply state of the plurality of power source device201-204. In a preferred embodiment of the present invention, the powersupply state of the plurality of power source devices 201-204 can bedirectly measured from the power connectors of the input terminal 411. Acombination of power supply state of the power source devices 201-204can be represented by a signal, i.e., the combination of signalsreceived by the detecting circuit 413 from the input terminal 411. Othermethods for detection and for expressing a combination of the powersupply state of a plurality of power source devices can also be appliedto the present invention.

In the illustrated example, the power supply state of each power sourcedevice 201-204 may be represented by a code digit. For example, codedigit 1 represents power good (normal), and code digit 0 representsfailure or shutdown. In this way, for 4 power source devices there aretotally 16 possible power supply state combinations, representable by 16codes.

In the known technology, in order to ensure the normal operation of thePoE system having multiple power source devices, it is necessary toprovide a mechanism for rapid shutting off power supplied to asufficient number of power consuming devices, when any power sourcedevice fails. This mechanism can prevent the system from total shuttingdown, due to failure of a small number of power source device. In theknown arts, such as the aforementioned patents, a look-up-table, call apower supply to power consumption look-up-table, is provided, to definethe corresponding relation of a plurality of power supply statecombination to a plurality of power consumption control combination. Forexample, when all the power source devices are operating normally (powersupply state: 1, 1, 1, 1), all port, such as 8 ports, are in the powerconsumption state (powered consumption state: 1, 1, 1, 1, 1, 1, 1, 1).However, when one power source shuts down, specific ports, such as portswith a lower priority value, needs to be shut off power supply, i.e.,their corresponding port switches need to be turned OFF. Thecorresponding relation of the then power supply state combination andthe power consumption control combination can thus be expressed as (1,1, 1, 0/1, 1, 1, 1, 1, 1, 1, 0). The remaining combinations of thelook-up-table can be easily appreciated by any skilled person.

Among the above codes, the code indicating the power consumption state,i.e., the ON/OFF state of the port switch, in correspondence with onepower supply state combination, can be referred to as a power consumingcontrol combination. When it is expressed by a signal or a controlsignal, it is a power consuming control signal.

This kind of the conventional power supply to power consumptionlook-up-table will not work, if a PoE system has a large number of powerconsuming devices. One of the reasons is, although the number of thedigit of each code in the power supply to power consumptionlook-up-table is not limited, a lengthy signal would be necessary, whenthe length of the power consumption control code is lengthy, forexample, with 64, 128, 256 or more digits. The lengthy signal would makethe system footprint larger and structure complicated, and offset allthe advantages of using a look-up table. The use of a control device tocontrol the power consumption of a greater number of electrical devicesis already an expected application. To design a useful control devicefor the power over Ethernet system having relatively large number ofpower source/consuming devices, this problem must be overcome.

Although it is not desirable to be bound by any theory, the inventorsfound that all PoE systems use a serial bus. When a control signal isquite lengthy (the number of digits of the signals is quite large), theserial bus becomes suitable for carrying the control signals. Using theexisting serial bus to transmit switch control signals to the pluralityof port switches can eliminate the need for a large number of wires.

According to the design of the first embodiment of the presentinvention, the master controller 410 is not configured to generate powerconsumption control signals, for directly providing to the individualport switches 311-31N. In the present invention, the control signalsgenerated by the master controller 410 is transmitted to one or more ofthe plurality of control circuits 421-42N, which in turn respectivelyprovides the power consumption control signals to the individual portswitch 311 to 31N. In order to shorten the process time and to achieveproper control, the invented control device 400 uses a serial signal bus430 to transmit the control signals of the master controller 410 to theplurality of control circuits 421-42N, as well as data and controlsignals exchanged among the plurality of control circuits 421-42N.According to a preferred embodiment of the present invention, the serialsignal bus 430 preferably uses the IIC communication protocol(Inter-Integrated Circuit Protocol).

To achieve the above objectives, the master controller 410 of thepresent invention provides a detection circuit. 413 in connection withthe input terminal 411, to inspect the power supply state of each powersource device and to generate a power supply state signal as a result ofthe inspection. Each signal represents one combination of the powersupply state, as power good or failure of the plurality of power sourcedevices. As a result, the inspection result of the detection circuit 413represents a combination of power supply states of the power supplydevices. The master controller 410 also provides a first look-up-tablememory 415 for storing a first power supply to power consumptionlook-up-table, which indicates the corresponding relation between aplurality of power supply state combinations and a plurality of powerconsumption control combinations. In the preferred embodiments of thisinvention, the first power supply to power consumption look-up-tabledefines a corresponding relation between a plurality of power supplystate signals and a plurality of power consumption control signals,and/or between a plurality of power supply state codes and a pluralityof power consumption control signals. For details of the structure andcontent of this power supply to power consumption look-up-table, pleaserefer to the foregoing description or any known prior art. Inapplication, the content of the power supply to power consumptionlook-up-table may be set manually, or set by the master controller 410automatically at the initial stage. The method of setting the contentsof the power supply to power consumption look-up-table is also a knowntechnology. Detailed description thereof is thus omitted.

The master controller 410 also provides a control signal generatingcircuit 414, which is connected to the detection circuit 413 and thefirst look-up-table memory 415. The control signal generating circuit414 is configured to generate a power consumption control signal upondetection of a change in the power supply state signal by the detectioncircuit, and provide the power consumption control signal to the controlcircuits 421-42N, to be further described below. The picked-up powerconsumption control signal corresponds to the power supply state signalreceived by the detection circuit 413.

To achieve the above objective, the detection circuit 413 may beconfigured to generate a power supply state change signal when thereceived power supply state signal is different from the previous powersupply state signal. After the control signal generating circuit 414receives the power supply state change signal, a power consumption statechange program is activated, whereupon it generates a power consumptioncontrol signal based on the power supply state signal newly received bythe detection circuit 413. In application, the detection circuit 413 maywired the outputs of the plurality of power source device, before theyenter the input terminal 411, whereby a change in the power supply stateof any power source device would generate a power supply state changesignal, to activate the power consumption state change operation. Fordetails of such implementation, reference may be made to the prior artmaterial described above.

FIG. 2 shows N control circuits 421-42N are connected to the serialsignal bus 430, and are connected communicatively to the mastercontroller 410 by the serial signal bus 430. All or most of the controlsignals are transmitted via the serial signal bus 430. The controlcircuits 421-42N are respectively connected with the port switches311-31N to control the operation of the port switches 311-31N. Each portswitch 311-31N controls the power consumption state of at least onecommunication port 301-30N (not shown in FIG. 2). When a switch is ON,the corresponding port receives power from the PoE system; otherwise,when the switch is OFF, the corresponding port receives no electricalpower. Each control circuit 421-42N uses the power consumption statecontrol signal to control the above-mentioned operation of thecorresponding port switch 311-31N. Each of the communication ports301-30N is connectable by a power consuming device (not shown).

In a preferred embodiment of the present invention, the respectivecontrol circuits 421-42N may further comprise a second look-up-tablememory 416, for storing a second power supply to power consumptionlook-up-table. This second power supply to power consumptionlook-up-table defines the corresponding relation of a plurality of powersupply state combinations and a plurality of power consumption statecontrol combinations. In this embodiment, each of the plurality of powerconsumption state control combinations corresponds to a switch statecombination of the port switches 311-31N connected to the controlcircuits 421-42N. In the application, the second power supply to powerconsumption look-up-table stored in the second look-up-table memory 461is the first power supply to power consumption look-up-table stored inthe look-up-table memory 415. In application, the second power supply topower consumption look-up-table defines a corresponding relation of aplurality of power supply state signals and a plurality of powerconsumption control signals and/or a corresponding relation of aplurality of power supply state codes and a plurality of powerconsumption control signals.

Therefore, in this embodiment, the master controller 410 may beconfigured to provide at the initial stage of the system, the firstpower supply to power consumption look-up-table pre-stored in the firstlook-up-table memory 415 to at least one of the plurality of controlcircuits. The so-called at least one means that it is not necessary forall control circuits 421-42N to provide a second look-up-table memory461. Only one of the plurality of control circuits 421-42N, for example,the control circuit 421, needs to provide the second look-up-tablememory 461. In such an implementation, the at least one control circuit.421 stores the first power supply to power consumption look-up-table inthe second look-up-table memory 416, after the table is received, forfurther use.

When the detection circuit 413 detects a change in the power-supplystate signal, the control signal generating circuit 414 converts thenewly received power supply state signal into a code and provides thecode to the at least one control circuit 421, to function as the powersupply state change signal. In application, the code can be any coderepresenting one of all possible combinations of the power supply state.The simplest way is to express the above-mentioned signal of powersupply state in a binary code. The binary code may be directly convertedinto a series of signals, such as a pulse series, representing thehexadecimal value of the binary code. For example, when the signal ofthe power supply state is 0101, the value of 0101 is converted into code5 to generate a pulse of 0000 0000 0001 0000. By simply adding anoperation code to the power supply state code, the code may betransmitted to the plurality of control circuits 421-42N via a serialbus at the same time through a well-known communication protocol, suchas the aforementioned IIC communication protocol, without addingadditional lines.

In this particular embodiment, after the at least one control circuit421 or the plurality of control circuits 421-42N receives the powersupply state code, it can pick up a corresponding power consumptioncontrol signal from the power supply to power consumption look-up-tablestored in the second look-up-table memory 461 and transmit it to allport switches 311 to 31N in connection with the control circuit 421 orthe plurality of control circuits 421-42N. In the case where only onecontrol circuit 421 is equipped with the second look-up-table memory461, the control circuit 421 can also transmit a picked up group ofpower consumption control signals to others control circuits 422-42N viathe serial signal bus 430, whereby each of the other control circuits422-42N transmits the corresponding power consumption control signal tothe connected port switches.

FIG. 3 is schematic structural diagram of a second embodiment of theinvented control device for power over Ethernet system having multiplepower source device. The components that are the same as those in FIG. 2will use the same or similar reference numbers.

The circuit structure and features of the second embodiment arebasically the same as or similar to the first embodiment, except that,as shown in FIG. 3, the control signal generating circuit 414 picks up apower consumption control code corresponding to a newly received powersupply state signal from the power supply to power consumptionlook-up-table and uses the code to generate the power consumptioncontrol signal directly, after the detection circuit 413 generates thepower supply state change signal. The control signal so generated isthen transmitted to the signal bus 430. To be more specific, when thedetection circuit 413 detects a change in the power supply statecombination, the control signal generation device 414 picks up a powerconsuming control code corresponding to the newly received power supplystate signal from the power supply to power consumption look-up-table,and uses the code as the power consumption control signal. It thenprovides the control signal to the plurality of control circuits 421-42Nvia the signal bus 430.

In order to make the power consumption control signal shorter, a powerconsumption control signal corresponding to a power supply statecombination can be divided by, for example, the number of the controlcircuits 421-42N, to obtain multiple power control signals. Each timeonly a partial power consumption control signal is transmitted. Asmentioned above, because of the serial signal bus 430, the partial powerconsumption control signal will be received by the right control circuit421-42N as long as a correct operation code is added. It takes about 128clock cycles to transmit 16 power consumption state control signals inthis way, and the operation of powering off the corresponding portswitch can still be completed within the required time. In such anembodiment, the multiple power consumption control signals may containcodes indicating related control circuits. In such embodiments, one(partial) power consumption control signal can correspond to one or morecontrol circuits. Therefore, the number of the control circuits isidentical or is a multiple of the number of the (partial) powerconsumption state control signals.

In such embodiments, each control circuit 421-42N provides the controlsignal a respectively corresponding port switch 311 to 31N, to enable ordisable power supplied to the individual communication ports 301-30N,after receiving the control signal. In such embodiments, each controlcircuit 421-42N does not need to be equipped with a look-up-tablememory.

FIG. 4 is schematic structural diagram of a third embodiment of theinvented control device for power over Ethernet system having multiplepower source device. The components that are the same as those in FIG. 2and FIG. 3 will use the same or similar reference numbers.

Circuit structure and features of the third embodiment are substantiallythe same or similar with the first and second embodiment, except that,as shown in FIG. 4, in the initial stage of the system, the mastercontroller 410 divides the power supply to power consumptionlook-up-table pre-stored in the first look-up-table memory 415 into aplurality of sub-tables, and provides each sub-table to thecorresponding one of the plurality of control circuit 421-42N. Eachsub-table only defines the corresponding relation of a plurality ofpower supply state combination and a plurality of power consumptioncontrol signal to be provided to the port switches 311-31N connected tothe respective control circuits 421-42N. The plurality of controlcircuit 421-42N, in turn, is configured to store the sub-table in thesecond look-up-table memory 461, after receiving the sub-table, and topick up a power consumption control signal corresponding to a receivedpower supply state signal from the power supply to power consumptionlook-up-sub-table and to provide the control signal to the port switches311-31N in connection with the respective control circuits 421-42N,after the power supply state code is received.

In other words, in the embodiment shown in FIG. 2, in the secondlook-up-table memory 461 of the at least one control circuit 421, a fulltable of the power supply to power consumption look-up-table may bestored (see FIG. 2). The full table defines the corresponding relationof the plurality of power supply state combination and the plurality ofpower consumption state control combination of all port switches311-31N. On the other hand, in the embodiment of FIG. 4, in the secondlook-up-table memory 461 of each control circuit 421-42N, a sub-table ofthe power supply to power consumption look-up-table is stored. Thesub-tables define the corresponding relation of the plurality of powersupply state combination and the plurality of power consumption controlsignals to be provided to the port switches 311-31N that are connectedto the respective control circuits 421-42N, only.

In the embodiment of FIG. 4, when the master controller 410 detects achange in the power supply state signal, it transmits the power supplystate signal, preferably in a form of a power supply state code, to thecontrol circuits 421-42N via the serial signal bus 430. Control circuits421-42N then uses the power supply state code to pick up a correspondingcontrol signal from the power supply to power consumptionlook-up-sub-table and provides the control signal to each of the portswitches 311 to 31N connected to the respective control circuit 421-42N.The power consumption state change operation is thus accomplished. Inthe example shown in FIG. 4, the power supply state code includes anoperation code and a code of the same number of pulses as that of theplurality of power supply state combination, and is transmitted to allcontrol circuits 421-42N in a single step. Only a few steps are requiredto complete the operation of powering off the corresponding portswitches.

FIG. 5 is schematic structural diagram of a fourth embodiment of theinvented control device for power over Ethernet system having multiplepower source device. The components that are the same as those in FIGS.2-4 will use the same or similar reference numbers.

This embodiment can be regarded as a modification of the embodiment inFIG. 4. As shown in FIG. 5, among the control circuits 421-42N of thefourth embodiment, the role of the control circuit 421 is equivalent tothe master controller 410 in the previous embodiments. The controlcircuit 421 has its input terminal 411 connected to the plurality ofpower source devices 201-204, and comprises a detection circuit 413 anda control signal generating circuit 414, which are equivalent to thedetection circuit 413 and the control signal generating circuit 414 ofthe first embodiment. In addition, the control circuit 421 is equippedwith a look-up-table memory 415 to store a power supply to powerconsumption look-up-table. What is different from the master controller410 of previous embodiments is, the control circuit 421 is connectedwith a plurality of port switch 311 to 31N, just like the other controlcircuits 422-42N. The EEPROM in the control apparatus 400 shown in thisfigure is used to provide an initial power setting for access by thecontrol circuit 421, for initial value setting.

The control circuit 421 is configured to read the initial power settingvalue from the EEPROM during the system startup stage, and divide thepower supply to power consumption look-up-table stored in advance in thelook-up-table memory 415 into a plurality of sub-tables, and provideeach sub-table to one of the other control circuits 422-42N. Eachsub-table only defines the corresponding relation of the plurality ofpower supply state combination and the plurality of power consumptioncontrol signals of the port switches 311-31N connected to the respectivecontrol circuits 421-42N.

In the embodiment of FIG. 5, when the control circuit 421 detects achange in the power supply state combination, it transmits a powersupply state signal, preferably a power supply state code, to the othercontrol circuits 422-42N via the serial signal bus 430. The controlcircuit 421 and the other control circuits 421-42N then uses the powersupply state code to pick up a corresponding power consumption controlsignal from the power supply to power consumption look-up-sub-table, orthe full table, and provides the control signal to each of the portswitches 311 to 31N connected to the respective control circuit 421-42N.The power consumption state change operation is thus accomplished. Inthe example shown in FIG. 5, the power supply state code includes anoperation code and a code of the same number of pulses as that of theplurality of power supply state combination, and is transmitted to thecontrol circuits 422-42N, other than the control circuit 421, in asingle step. Only a few steps are required to complete the operation ofpowering off the corresponding port switches.

Although the invention has been described with reference to specificembodiments, this description is not meant to be construed in a limitingsense. Various modifications of the disclosed embodiments, as well asalternative embodiments, will be apparent to persons skilled in the art.It is, therefore, contemplated that the appended claims will cover allmodifications that fall within the true scope of the invention.

What is claimed is:
 1. A control device for power over Ethernet (PoE)system having multiple power source device, to control a powerconsumption state of a plurality of communication ports in the system;wherein the PoE system comprises a plurality of power source device anda combination of power supply state of the plurality of power sourcedevice at one time forms a power supply state combination; the controldevice comprising: a master controller, comprising: an input terminalfor connecting a plurality of power source devices to receive a powersupply state signal representing a power supply state combination of theplurality of power source devices; a detection circuit connected to theinput terminal for detecting the power supply state signal and forgenerating a power supply state change signal, when a power supply statesignal received by the detection device is different from a previouslyreceived power supply state signal; a first look-up-table memory tostore a first power supply to power consumption look-up-table defining acorresponding relation of a plurality of power supply state combinationto a plurality of power consumption control combination; and a controlsignal generating circuit connected to the detection circuit andconfigured to: generate, upon receipt of a power supply state changesignal, a power supply state code corresponding to the received powersupply state signal; a plurality of control circuits connected to themaster controller and a plurality of port switches, each port switchcontrolling a power consumption state of at least one port to beconnected by a power consuming device; wherein each control circuit isconfigured to generate, upon receipt of the power supply state code, apower consumption control signal corresponding to the power supply statecode and to provide the power consumption control signals tocorresponding port switches, to determine a power consumption state ofcorresponding ports; and a signal bus connected to the master controllerand the plurality of control circuits; wherein, the signal bus is aserial bus.
 2. The control device for PoE system having multiple powersource devices according to claim 1, wherein the first and/or secondpower supply to power consumption look-up-table defines a correspondingrelation of a plurality of power supply state signals and a plurality ofpower consumption control signals and/or a corresponding relation of aplurality of power supply state codes and a plurality of powerconsumption control signals.
 3. The control device for PoE system havingmultiple power source devices according to claim 1, wherein the signalbus uses the IIC communication protocol.
 4. The control device for PoEsystem having multiple power source devices according to claim 1,wherein at least one control circuit comprises a second look-up-tablememory, to store a second power supply to power consumptionlook-up-table, wherein the master controller is configured to: in theinitial stage of the system, provide the first power supply to powerconsumption look-up-table stored in the first look-up-table memory tothe at least one control circuit and to convert, upon receipt of thepower supply state change signal, the received power supply state signalinto a power supply state code and provide the code to the at least onecontrol circuit; and wherein the at least one control circuit isconfigured to: after receiving the power supply to power consumptionlook-up-table provided by the master controller, store the power supplyto power consumption look-up-table in the second look-up-table memory,and to pick up, after receiving the power supply state code, acorresponding power consumption control signal from the power supply topower consumption look-up-table and provide the power consumptioncontrol signal to a port switch in connection with the control circuit.5. The control device for PoE system having multiple power sourcedevices according to claim 4, wherein the first and/or second powersupply to power consumption look-up-table defines a correspondingrelation of a plurality of power supply state signals and a plurality ofpower consumption control signals and/or a corresponding relation of aplurality of power supply state codes and a plurality of powerconsumption control signals.
 6. The control device for PoE system havingmultiple power source devices according to claim 4, wherein the signalbus uses the IIC communication protocol.
 7. The control device for PoEsystem having multiple power source devices according to claim 1,wherein each control circuit further comprises a second look-up-tablememory, to store a second power supply to power consumptionlook-up-table; wherein the master controller is configured to: in theinitial stage of the system, provide the first power supply to powerconsumption look-up-table stored in the first look-up-table memory tothe plurality of control circuit, and to convert, upon receipt of thepower supply state change signal, the received power supply state signalinto a power supply state code and provide the code to the plurality ofcontrol circuits; and wherein the plurality of control circuit isconfigured to: after receiving the power supply to power consumptionlook-up-table provided by the master controller, store the power supplyto power consumption look-up-table in the second look-up-table memory,and to pick up, after receiving the power consumption state code, onecorresponding power consumption control signal from the power supply topower consumption look-up-table, and provide the power consumptioncontrol signal to a port switch in connection with the control circuit.8. The control device for PoE system having multiple power sourcedevices according to claim 7, wherein the first and/or second powersupply to power consumption look-up-table defines a correspondingrelation of a plurality of power supply state signals and a plurality ofpower consumption control signals and/or a corresponding relation of aplurality of power supply state codes and a plurality of powerconsumption control signals.
 9. The control device for PoE system havingmultiple power source devices according to claim 7, wherein the signalbus uses the IIC communication protocol.
 10. The control device for PoEsystem having multiple power source devices according to claim 1,wherein each control circuit further comprises a second look-up-tablememory, to store a power supply to power consumption look-up-table;wherein the master controller is configured to: in the initial stage ofthe system, divide the first power supply to power consumptionlook-up-table stored in the first look-up-table memory into a pluralityof sub-tables and provide the sub-table to corresponding one of theplurality of control circuit; wherein the plurality of control circuitis configured to: after receiving the power supply to power consumptionlook-up-sub-table provided by the master controller, store the powersupply to power consumption look-up-sub-table in the secondlook-up-table memory, and to pick up, after receiving the powerconsumption state code, a corresponding power consumption control signalfrom the power supply to power consumption look-up-sub-table, andprovide the power consumption control signal to a port switch inconnection with the control circuit.
 11. The control device for PoEsystem having multiple power source devices according to claim 10,wherein the first and/or second power supply to power consumptionlook-up-table defines a corresponding relation of a plurality of powersupply state signals and a plurality of power consumption controlsignals and/or a corresponding relation of a plurality of power supplystate codes and a plurality of power consumption control signals. 12.The control device for PoE system having multiple power source devicesaccording to claim 10, wherein the signal bus uses the IIC communicationprotocol.
 13. The control device for PoE system having multiple powersource devices according to claim 1, wherein the master controller isconnected to a plurality of port switches, each controlling powersupplied to at least one port; wherein each control circuit furthercomprises a second look-up-table memory, to store a power supply topower consumption look-up-table; wherein the master controller isfurther configured to: in the initial stage of the system, provide thefirst power supply to power consumption look-up-table stored in thefirst look-up-table memory to the plurality of control circuit, and toconvert, upon receipt of the power supply state change signal, thereceived power supply state signal into a power supply state code andprovide the code to the plurality of control circuits; wherein theplurality of control circuit is further configured to: after receivingthe power supply to power consumption look-up-table provided by themaster controller, store the power supply to power consumptionlook-up-table in the second look-up-table memory, and to pick up, afterreceiving the power consumption state code, one corresponding powerconsumption control signal from the power supply to power consumptionlook-up-table, and provide the power consumption control signal to aport switch in connection with the control circuit; and wherein themaster controller is further configured to: after generating the powerconsumption state code, pick up one corresponding power consumptioncontrol signal from the power supply to power consumption look-up-table,and provide the power consumption control signal to a port switch inconnection with the master controller.
 14. The control device for PoEsystem having multiple power source devices according claim 13, whereinthe first and/or second power supply to power consumption look-up-tabledefines a corresponding relation of a plurality of power supply statesignals and a plurality of power consumption control signals and/or acorresponding relation of a plurality of power supply state codes and aplurality of power consumption control signals.
 15. The control devicefor PoE system having multiple power source devices according to claim13, wherein the signal bus uses the IIC communication protocol.
 16. Thecontrol device for PoE system having multiple power source devicesaccording to claim 1, wherein the power supply state signal has the samenumber of code digit as the number of the plurality of power sourcedevices.
 17. The control device for PoE system having multiple powersource devices according to any of claim 1, wherein the power supplystate code is equivalent to a result of converting the power supplystate signal into a serial signal.
 18. The control device for PoE systemhaving multiple power source devices according to claim 4, wherein theat least one control circuit is configured to pick up a powerconsumption control signal from the power supply to power consumptionlook-up-table and provide the power consumption control signal to othercontrol circuits via the signal bus.
 19. The control device for PoEsystem having multiple power source devices according to claim 18,wherein the at least one control circuit picks up a power consumptioncontrol data corresponding to the power supply state code from the powersupply to power consumption look-up-table, to generate the powerconsumption control signal.
 20. A control device for power over Ethernet(PoE) system having multiple power source device, to control a powerconsumption state of a plurality of communication ports in the system;wherein the PoE system comprises a plurality of power source device anda combination of power supply state of the plurality of power sourcedevice at one time forms a power supply state combination; the controldevice comprising: a master controller, comprising: an input terminal,connected to the plurality of power source devices to receive a powersupply state signal representing a combination of power supply state ofthe plurality of power source devices; a detection circuit connected tothe input terminal to detect a change in the power supply statecombination according to the received power supply state combinationsignal; a first look-up-table memory to store a first power supply topower consumption look-up-table defining a corresponding relation of aplurality of power supply state combination and a plurality of powerconsuming control combination; and a control signal generating circuitconnected to the detection circuit and configured to: pick up, afterdetection of a change in the power supply state combination by thedetection circuit, a power consumption control data corresponding to thereceived power supply stage signal from the first power supply to powerconsumption look-up-table, divide the power consumption control datainto a plurality of power consumption control signals and output thepower consumption control signals; wherein each power consumptioncontrol signal corresponds to at least one control circuit; and aplurality of control circuit connected to the master controller and aplurality of port switches, each port switch controlling a powerconsumption state of at least one port for connection by a powerconsuming device; wherein each control circuit is configured to: uponreceipt of the power consumption control signal, provide the powerconsumption control signals to corresponding port switches, to enable ordisable power supplied to respective ports; and a signal bus connectedto the master controller and the plurality of control circuits; wherein,the signal bus is a serial bus.
 21. The control device for PoE systemhaving multiple power source devices according to claim 20, wherein thecontrol signal generating circuit is configured to transmit one of theplurality of power consumption control signals at a time.
 22. Thecontrol device for PoE system having multiple power source devicesaccording to claim 20, wherein the quantity of the control circuits isidentical or is a multiple of the number of the power consumptioncontrol signals.
 23. The control device for PoE system having multiplepower source devices according to any of claim 20, wherein the firstpower supply to power consumption look-up-table defines a correspondingrelation of a plurality of power supply state signals and a plurality ofpower consumption control signals and/or a corresponding relation of aplurality of power supply state codes and a plurality of powerconsumption control signals.
 24. The control device for PoE systemhaving multiple power source devices according to any of c claim 20,wherein the signal bus uses the IIC communication protocol.
 25. Thecontrol device for PoE system having multiple power source devicesaccording to any of claim 20, wherein the power supply state signal hasthe same number of code digit as the number of the plurality of powersource devices.